Does what I said make sense?

The question set was ''use human blood grouping to describe the concept of codominance''.

My answer is:

''Blood type AB is codominant. In codominance both alleles are expressed in the phenotype of individuals that have heterozygous alleles. Both alleles in the heterozygous genotype express themselves fully.

This means that the gene is expressive, for example, if there was a cross between two animals with codominant blood types they will both express their genes. For example if a black coloured cat is crossed between a grey coloured cat, they will produce a cat with a mixture of black and grey fur.''   


Do you think that's a good answer or not?

What do you think I can improve on?

Its an exam question and I'm expected to get 3 points for it.